When seniors in Sisters think "fitness" they may not picture themselves hoisting a barbell. But in fact, weight training is perhaps the most critical single component in senior fitness.

Harvard Medical School reports that, "Age-related muscle loss, called sarcopenia, is a natural part of aging. After age 30, you begin to lose as much as three to five percent per decade. Most men will lose about 30 percent of their muscle mass during their lifetimes.

"Less muscle means greater weakness and less mobility, both of which may increase your risk of falls and fractures. A 2015 report from the American Society for Bone and Mineral Research found that people with sarcopenia had 2.3 times the risk of having a low-trauma fracture from a fall, such as a broken hip, collarbone, leg, arm, or wrist."

Dr. Thomas W. Storer, director of the exercise physiology and physical function lab at Harvard-affiliated Brigham and Women's Hospital argues that the best means to build muscle mass, no matter your age, is progressive resistance training (PRT). With PRT, you gradually amp up your workout volume-weight, reps, and sets-as your strength and endurance improve.

PRT improves and preserves muscle mass, bone density and ligament strength, making seniors fitter, stronger - and safer. The stronger you are, the less likely you are to fall and the more likely you are to avoid or recover from injury if you do.

And you don't have to lift like an NFL linebacker to get the benefits.

"It doesn't matter what the weight is," says Ryan Hudson, a strength coach and owner of Level 5 CrossFit Sisters. "Bodyweight exercise is great; external load is better and both is ideal."

Hudson acknowledges that the idea of weight training can be a little overwhelming for seniors, especially if they've lost a lot of strength and fitness.

"A lot of them feel a little intimidated by it, because they're not strong," Hudson said

The key is to start "low and slow" and build capability gradually. Someone new to resistance training or who has been away for a long time might want to start with bodyweight exercise, perhaps provided by a yoga or Pilates class.

"It's something anybody can do," Hudson emphasized.

It often takes only a little time before a senior starts feeling much better, much stronger.

Hudson says he has a client who started lifting in her 70s.

"She's just amazed at what she's able to do after just a few months of this," he said.

Often, he says, older clients are excited by their results and "they wonder why they didn't do it sooner."

Not all forms of resistance training are created equal. Oftentimes, a new lifter will feel more comfortable using machines, which require less technique to use properly. But Hudson strongly encourages the use of barbells, dumbbells, kettlebells - what are generally known as "free weights."

"It needs to be functional movement," he says. "It should be core-based and ground based. You should be standing on your feet to do your resistance training."

Combined with a good diet, resistance training can be a tremendous boon for seniors - improving quality of life across the board.

Harvard Medical School advises that seniors "Check with your doctor before embarking on any kind of strength-training routine. Then enlist a well-qualified personal trainer to help set up a detailed sequence and supervise your initial workouts to ensure you perform them safely and in the best manner. As you progress, you can often perform them on your own."

While Hudson coaches all levels and all ages, he is particularly keen to see more seniors working in the gym.

"If anything," he says, "older people need it more than younger people do."